Many halogenated and nitroaromatic organic chemical contaminants in the environment are highly resistant to degradation. Once the halogenated organic chemical contaminant is dehalogenated or the nitro groups are reduced to amine groups, the organic contaminants are usually degraded easily, generally by aerobic microbial processes. Degradation of organic contaminants in microbial ecosystems occurs both by enzymatic and non-enzymatic mechanisms. Most enzymatic reactions involve whole microbial cells such as bacteria, fungi, and algae. Enzymatic reactions are usually more specific than non-enzymatic reactions, but the activity of enzymatic reactions is destroyed by harsh conditions such as exposure to high temperatures. Microbial activity can assist degradation of organic contaminants either directly by enzyme production or indirectly by maintaining the reducing conditions of the environment. Either way, microbial activity enhances both the inorganic and biochemical mechanisms by which degradation of organic contaminants occurs.
Currently, certain environmental remediation methods employ the use of relatively small, finely comminuted, segregated particles of various types of materials that are typically mixed on site, in proportions and amounts selected by on-site personnel. For example, where such materials are used, on-site personnel are required to thoroughly mix quantities of the various components and, in most instances, incubate small batches of mixtures to establish sufficient beneficial microbial growth to permit use. The personnel must then apply those incubated components into the target environment. In these prior art systems, on-site personnel have used iron filings alone, comminuted fibrous organic materials alone, iron filings combined and then mixed on site with comminuted fibrous organic materials or iron filings mixed on site with sand.
Many earlier systems using iron filings alone, comminuted organic materials alone, or even iron filings with sand, are often ineffective in treating sites which are contaminated with various organic chemicals. Each of these systems sought to use individual ingredients provided in the form of relatively fine, segregated particles of one or more ingredients, to obtain a relatively high reactive surface area per volume (and hence weight and expense) of the material to be added to the contaminated site.
Even those systems contemplating the use of more than one additive encounter problems relating to on-site measurement, mixing, and application of the ingredients to the target area. By way of example, there is a tendency for on-site personnel to inadequately mix the desired components, often leading to pockets or zones with too much or too little of a desired ingredient. Even if the ingredients were adequately mixed, the ingredients might not be mixed in appropriate ratios to achieve target concentrations determined to be optimal for the particular application. Mixtures of two or more ingredients also had a tendency to stratify due to differences in physical properties such as density and average particle sizes. In addition, even where prior art systems contemplated the mixture of fine particles of two or more ingredients, various transportation and handling problems would arise. Some ingredients tended to generate dust and other unpleasant handling conditions for on-site personnel.
Therefore, there is a need for a composition for treating contaminated regions that is easy to use, economical, and effective.